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--- hardware:channels:meters:power:swissnox_s-watt [2011/05/30 03:30] – second eeprom r00t
+++ hardware:channels:meters:power:swissnox_s-watt [2018/03/25 11:08] (aktuell) – alte Version wiederhergestellt (2013/02/10 13:15) jau
@@ Zeile 1: / Zeile 1: @@
-==== Swissnox S-Watt ====
+====== Swissnox S-Watt ======
-{{:hardware:channels:meters:power:swissnox_s-watt:s-watt_internal.jpg?640}}
-=== opening ===
+The Swissnox S-Watt is a cheap S0-Impulse energy meter. Its available on eBay and Amazon for around 18 €.
-the two halves of the case are held together by the (snapped on) covers at the terminals, and slighty glued at the bottom.
-jam a large scredriver in between the case and covers from the bottom (remove the rail clip first, also using a little violence), and pry them off (in some of my devices some glue got in there too, tough luck).
-then gentry pry apart the side covers from the display side, until the glue breaks.
-=== Energy Metering IC ===
+{{:hardware:channels:meters:power:swissnox_s-watt:s-watt_internal.jpg?400}}
-chip is labeled "ate7755", but google turns up nothing for that.
-it appears that it's a clone of the analog devices ADE7755. all pins i checked so far match the ade7755 pinout.
+===== Modification to get a high pulse-rate output =====
+By doing a few easy steps, you can change your S0 Output to a very high frequency output.
+See schematic below. Black wires are already there. Grey wires are also there but only for layout purposes. The red wire shows, where u have to work.
+{{:hardware:channels:meters:power:swissnox_schematic.png?300|}}
+It's very easy to do. Just lift one pin of the Optocoupler and connect it to a via as shown in the picture.
+{{:hardware:channels:meters:power:swissnox_mod.jpg?300|}}
+And you're done!
+==== Result ====
+Signal output with a 2,7k pull-down and 9V battery on S0 Output.
+**One Peak:**
+{{:hardware:channels:meters:power:swissnox_osc_1peak.png?300|}}
+**40W Bulb**
+{{:hardware:channels:meters:power:swissnox_osc_40w.png?300|}}
+**2000W Hair dryer**
+{{:hardware:channels:meters:power:swissnox_osc_2000w.png?300|}}
+==== Calibration ====
+Calibration can be done very easy when you read out the eeprom.
+The value on 0x03 multiplied by 2000 is the High Speed imp/kWh.
+In the case of the first Swissnox above: 0xCF * 2000 = 410.000 imp/kWh
+I verified this, by counting the 7755 pulses between the pulses of the normal S0 output. They are exactly the value 0x03 of the eeprom!
+Note that 410.000 imp/kWh are not set in stone. After modifying 16 S-Watts and recalibrating them using actual measurement rather than reading the EEPROM, I found that mine are now between 242 and 256 times faster than before (that would be between 484.000 and 512.000 imp/kWh). Every S-Watt will behave differently after the modification and every one needs to be calibrated.
+== Impulse Width ==
+The width (duration) of an impulse drops from 70-90ms to 0.5ms after the modification. Depending on what counter you use and how many S-Watts you like to keep track of, it could be easy to miss a few pulses, so it is important to keep this in mind.
+It is also likely that with currents greater than 13 amperes (roughly 3000 Watts), the impulse width might decrease even further. Assuming we have an S-Watt measuring 10.000 Watts (it is certified up to 50 amperes = 11.500 Watts) and it produces 500.000 imp/kWh, we'd have 500.000 impulses every 6 minutes, or (roughly) 100.000 imp/min, or ~1400 imp/s. It is unknown to me how the S-Watt would handle such high impulse frequencies.
+==== ToDo ====
+  * <del>Calibrate</del>
+  * Process these impulses to use them with vz (i am working on that) -> Will be done by [[software:controller:vzlogger]].
+===== Internals =====
+==== Opening ====
+The two halves of the case are held together by the (snapped on) covers at the terminals, and slighty glued at the bottom.
+Jam a large screwdriver in between the case and covers from the bottom (remove the rail clip first, also using a little violence), and pry them off (in some of my devices some glue got in there too, tough luck).
+then gently pry apart the side covers from the display side, until the glue breaks.
+==== Energy Metering IC ====
+The chip is labeled "ATE7755", but google turns up nothing for that.
+It appears that it's a clone of the analog devices ADE7755. All pins i checked so far match the ADE7755 pinout.
 "Energy Metering IC with Pulse Output" -- http://www.analog.com/static/imported-files/data_sheets/ADE7755.pdf
@@ Zeile 15: / Zeile 70: @@
 {{:hardware:channels:meters:power:swissnox_s-watt:ade7755_pinout.png}}
-curiously, the only connection between the ATE7755 and the controller is the 7755's "CF" pin, which is, according to the datasheet:
+Curiously, the only connection between the ATE7755 and the controller is the 7755's "CF" pin, which is, according to the datasheet:
 > Calibration Frequency Logic Output. The CF logic output gives instantaneous active power information.
 > This output is intended to be used for calibration purposes. Also, see the SCF pin description.
-the normal pulse output pins (F1 and F2) are not connected. the output signal to the optocoupler is generated by the controller.
+The normal pulse output pins (F1 and F2) are not connected. The output signal to the optocoupler is generated by the controller.
-some measurements of the signal (kd302 used as reference):
+Some measurements of the signal (kd302 used as reference):
 {{:hardware:channels:meters:power:swissnox_s-watt:cf_40w.jpg?512}}
@@ Zeile 28: / Zeile 83: @@
 {{:hardware:channels:meters:power:swissnox_s-watt:cf_1760w.jpg?512}}
-| power (approx.) | pulse distance (approx.) |
+^ power (approx.) ^ pulse distance (approx.) ^
 | 37w  | 220ms |
 | 800w | 11ms |
 | 1760w | 5ms |
-that just leaves the question of how calibration is handled...
+That just leaves the question of how calibration is handled.
-=== controller ===
+==== Controller ====
   * 4-bit OTP controller: http://www.google.com/search?q=sh67p53p
-=== eeprom ===
+==== EEPROM ====
 {{:hardware:channels:meters:power:swissnox_s-watt:eeprom_buspirate.jpg?512}}
 <code>
 I2C>W
@@ Zeile 56: / Zeile 112: @@
 READ: ...
 </code>
-this is from a device that's still at 0.00kWh:
+(When the large capacitor(?) is connected, the board can't be powered from the bus pirate, because it assumes there's a short. The board in the picture has the large power supply components removed for taking pictures of the PCB.)
+This is from a device that's still at 0.00kWh:
 <code>
 : 0x00 0xFF 0x00 0xCF 0xFF 0xFF 0xFF 0xFF
@@ Zeile 68: / Zeile 127: @@
 </code>
-this is the device used for the CF measurements, counter at 0.07kWh:
+This is the device used for the CF measurements above, counter at 0.07kWh:
 <code>
 : 0x00 0xFF 0x00 0xCD 0xFF 0xFF 0xFF 0xFF
@@ Zeile 78: / Zeile 137: @@
 [all 0xFF]
 F8: 0xFF 0xFF 0xFF 0xFF 0xFF 0xFF 0xFF 0x00
 </code>
-=== connectors ===
-== J2 ==
+So the second line must be the counter value, with unused places left at 0xFF.
+The first line (only difference between the two) must be the calibration value?
+==== Connectors ====
+=== J2 ===
 power, calibration, programming(?)
+^ pin ^ description ^
 |1 (at "J2" label)|+5V|
 |2|i2c SCL (eeprom)|
@@ Zeile 89: / Zeile 153: @@
 |5|i2c SDA (eeprom)|
 |6|GND|
+===== PCB Revisions =====
+Either there are different versions of the device, or the above schematic is not 100% correct.
+Also, a not connected pin on the controller is misused to route a trace (red) under the controller. ew...
+{{:hardware:channels:meters:power:swissnox_s-watt:swissnox_traced.jpg?512}}
+>> I dont think there are different versions of the device because your picture shows the same circuit as determined in the shematic above. Just the routing is different. Have a closer look.
+>>> In my device, CF is connected to portA.0, your schematic connects CF to portB.3, which is i2c SCL in my device.