M-Controller II System Operation Manual - 10 -
84350-201-001 Rev C
General Guideline:
Old M-Controller uses full-wave rectifier only, if the M-Controller II is supposed
to replace the old M-Controller, use TB7 for input power
Q5 and Q8 both have full-wave and half-wave rectifier
Old M-Relay, old M-Annunciator and QRP have a full-wave rectifier only
M-Relay SMT version and M-Annunciator SMT version have full-wave and half-
wave rectifier
It is okay to connect multiple devices to the same AC transformer and share signal
commons if
o Every device uses a same style rectifier
o And the same AC lead on every device is used for common
If the power supply is 24VAC and half-wave rectifier circuit is selected, no matter
it is GROUNDED (one side of AC is connected to ground), or FLOATING
(neither side of AC is connected to ground), the polarization is important, make
sure the Neutral or the same AC lead is connected to the GND of TB8. Make sure
the same AC lead is connected to ground in all devices that share the AC source.
Treat AC like DC for purposes of watching polarity in this case.
o For Q5, the TB5 of Q5 can only be connected to the same AC source
o For Q8, the TB6 of Q8 can only be connected to the same AC source
o For other devices, only the device with half-wave rectifier can be
connected to the same AC source. If it does not have, or any doubt exists,
provide a dedicated isolated transformer to the device
If the power supply is 24VDC, all the devices can be powered by the same DC
source.
Whenever you have different devices from different manufacturers, be careful to
separate those devices that utilize a Full-wave rectifier from those using a Half-
wave rectifier. When any doubt exists, provide a separate transformer. The small
expense of an additional transformer or two will more than make up for all of the
time and money spent on troubleshooting.
Please refer to M-Controller Installation Drawing for power & RS-485
Connection
It is necessary to bear in mind the actual installation when sizing the transformer.
The installation requirements can run theoretically from only 15 VA to over 200
VA.
It is always best to allow some safety margin in designing power supplies, and
25% to 50% allowance for startup surges and future requirements is
recommended.
M-Controller Common/Power Supply Negative is not connected to Chassis Safety
Ground. AI Common is connected to M-Controller Common. Therefore, the
power supplies for remote devices should be powered carefully to prevent ground
loops. Remote Relay Module Negative is not connected to Chassis Safety Ground.
All metal chassis are supplied with a safety ground to the case.
QEL supplies one standard transformer
M-Transformer 120 to 24 VAC 200 VA
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