I am having a problem with my KY124 meter, the units finished and I am using the batteries but it keeps saying NULL when I try to load the units, it keeps giving the same error code even when I try to check the balance. What could be the problem?
Hi Yembo
Did you manage to load new units yet?
Here's my
Tshwane prepaid meter problem / fault finding checklist (assuming the power is out/off/units ran out):
* If the power is off, the keypad will power from its own batteries, and display an open switch icon. Make sure the keypad batteries are fresh and have enough juice to get the communication signal all the way to the meter.
* NB: If you are running a generator or backup inverter, make sure to disconnect from your backup power, and have everything set as you would for normal munipical power usage. Changeover switches should be on mains power etc.
* NB: all trip switches and circuitbreakers in your DB must be set in the normal up/on positions.
* NB: plug the battery powered keypad into a wall socket as close to your DB box as possible. Make sure the socket switch is in the on position.
Above three tips are CRITICAL to ensure an uninterrupted AC wire connection between the KY124 keypad and PCR421 meter outside, even and especially when there is no power. The keypad uses Power Line Communication (PLC), piggy backing its high frequency comms signal on top of the 240V AC wiring in your house, all the way to the actaul meter/relay unit outside your house.
Now test the KY124 keypad using the following codes:
* press 007
It should state "PLC" (usually only on first try).
Then "Connect", then give the unit balance 0.00 kWh.
If it says "Error" or "Null" it means the keypad is unable to communicate with the pcr421 meter unit. Double check the above three tips. Also read
PLC lock-up below.
* Press 009. Should show "connect" then the current date. The date is being read from the meter and is a good indication that the PLC comms between the keypad and meter are working.
* Press
005 or 008 which gives your pcma serial number (I.e. pairing between keypad and meter still in place). This is read from the keypad memory only and should work even if the keypad is plugged out. An error here might indicate a faulty keypad or that the keypad needs to be re-paired with the meter.
Also go check your PCR421 meter outside too:
* With everything running normal, the pcr421 is flashing red the pulse led whilst the relay and alarm leds are off. I suspect if the units run out the relay will switch off the mains and turn the relay led amber.
* All LEDs/LCDs off probably means no mains power is feeding the meter (upstream problem). Check your neighbours and log a call with Tshwane.
* Alarm LED on means either some alarm threshold has been reached (though I don't think this facility works with the Tshwane meters) or perhaps the tamper protection has been tripped.
* The PCR421 actaully has a small oval grey push button next to the right of the barcodes. You can press this button safely and cycle between different data registers. If there is no power from the street, the meter has a small battery and pushing the button will momentarily enable the screen, allowing you to cycle between date/time/total usage. If there is street power to the meter, the screen will be on already and pushing the button will also light up the screen. Additional info accessible include pcma serial number (register # 96.1.1 and .2)/unit balance (coin icon, register # 19.0.0)/incoming mains voltage (register # 32.7.0)/immediate current consumption (register # 91.7.0) / current power consumption (register # 1.7.0). The latter two should be near zero if your house isn't drawing any power. If the meter doesn't respond or any of these registers seem unusual, your meter unit might be faulty.
* PLC lock-up: in some cases, the power line communication between your keypad and meter can lock-up during loadshedding or switching of the meter relay (e.g. when your units run out). You can try power cycling your keypad by opening and closing the battery compartment. At least in my case the meter had to be reset or power cycled, which is best done by a Tshwane technician or might happen automatically on the next loadshedding cycle. Supposedly Tshwane can also do a remote reset/restart of the meter (see below).
* Tamper mode or upstream comms lock-out: At least once after loadshedding, my meter also locked up like above (i.e. the keypad and meter would not communicate) but it remained off even after a loadshedding "restart". On the
meter LCD, there is a indicator that normally looks like this ●─·─● (closed switch), which changed and looked almost like this ●─┘┌─● (open switch). Note: this is on the PCR421
meter outside, not the
keypad LCD which has a similar indicator (but different meaning). On the PCR421 I think this means the meter cannot communicate upstream to Tshwane or has for whatever reason engaged the relay (failsafe or tamper) and interrupted supply even if you have credit or not. An overhead power technician (admittedly not an expert on the prepaid meters) looked at that indicator and said my meter is in tamper condition, and that it happens sometimes due to loadshedding. She phoned in and requested a remote reset or something. She said if that does not work, the meter technician would have to come out. A few minutes later the switch indicator closed and my keypad could communicated / load new vouchers again.
TL;DR: if your PCR421 has an open switch indicator, it might be worth logging a call
here with the following 50 character comment "PCR421 prepay meter open switch icon. Remote reset"