Manual ME-582x Series
Revision 0.9
3 Hardware
page 13
Meilhaus Electronic
The opto-isolated digital-inputs of the ME-5820 series are protected from
over-voltages with special Z-diodes, so called Transient Voltage Suppres-
sor diodes (TVS diodes). These diodes can discharge short voltage pulses
with U
RWM
(Reverse Working Maximum) greater than 64.4 V to ground
(max. 600 W pulse power at a pulse width of 1 ms).
3.4.2
Opto-Isolated Outputs
The ME-5820 has 16 opto-isolated outputs (port B), ME-5821 has 32 opto-
isolated outputs (port B and port D).
The ME-582x output ports are equipped with special driver chips that allow
a selection of sink and source via software. Depending on the application,
the user can switch between low-active outputs (sink driver = standard set-
ting) and high-active outputs (source driver) via software. Moreover, the
output ports can be set to high impedance. A reference to the ground of
the external wiring via GND_EXT (pins 9, 11, 59) has to be setup in any
case.
3.4.2.1
Sink Driver
Each output is equipped with two sink driver chips of type ULN2803, de-
tailed specifications see page 29.
Picture 5: ME-5820/21 outputs with sink drivers
The maximum current per output (I
C
= I
Sink
) depends on the saturation volt-
age U
CE
and is limited by the power loss of the sum of the channels on P
tot
= 1
W per chip (DO_x 0…7 = chip 1, DO_x 8…15 = chip 2), see picture 6
and 7.
P
tot
= P
0
+ … + P
7
≤ 1
W (per chip by 70 ºC)
with P
0
= I
C0
⋅
U
CE0
