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AcuRev 1300
AcuRev1300 communication utilizes RS485 port, via Modbus-RTU protocol. The
wiringterminals are A, B, S. "A" is called dierential signal " ", "B" is called dierentialsignal"-",
"S" is connected to the shielding of shielded twisted pair cable. The maximumdistance of
Shielded Twisted Pair cable is 1200 m. The distance will be shorter if moredevices are on the
same communication link or using a higher baud rate.
If the master device does not have RS485 but RS232 port, a RS232/485 converter can
beutilized. Typical RS485 network topologies include line, circle and star.
In order to improve communication quality, please pay attention to:
1. High-quality Shielded Twisted Pair cable is very important, AWG22 (0.6mm2) or
lower isrecommended. Two cables should be dierent colors.
2. Pay attention to "single point earthing". It means there is only one point of the
shieldingconnected to ground in a single communication link.
3. Every A(+) should be connected to A(+), B(-) to B(-), or it will inuence the network,
evendamage the communication interface.
4. "T" type connection topology should be avoided. This means no new branches
exceptfrom the starting point.
5.Keep communication cables away as much as possible from sources of electrical
noise.When several devices are connected (daisy chain) to the same long communication
line, ananti signalrefecting resistor (typical value 120- 300Ohm, 0.25W) is often used at the
endof the circuit (the last meter of the chain) if the communication quality is distorted.
6. Use RS232/RS485 or USB/RS485 converter with optical isolated output and surge
protection.
7. A infrared port is also available in the Display Module, which supports meterreading.
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