Manual ME-5310 Series
Revision 1.0E
3 Hardware
page 10
Meilhaus Electronic
At the pins 19, 20, 38, 39, 58, 59, 77 and 78 a signal of + 5 V from the PC
is available. The total load of these 8 pins should not exceed 500 mA.
The pin configuration of the 78-pin female D-Sub connector(s) can be
found in appendix B (see page 15).
Picture 2: Wiring of the ME-5310
It is important that the voltage levels of the digital input/output wiring is
within the TTL level-limits and that a reference to PC ground (PC_GND) is
made.
The current load of the board (without airflow) including the possibly used
pull-up resistors can be approximated using the following formula:
T
J
≥
T
u
+ (14
°
C/W x P
G
)
T
J
= max. specified operation temperature of the component of 70
°
C
P
G
= total load of the outputs used
T
u
= surrounding temperature (without convection)
The maximum output current of a single output is:
I
Out
= I
OL
= max. 20 mA bzw. I
Out
= I
OH
= max. 4 mA
3.2.2
Pull-Up/Pull-Down Resistors
On power-up, all ports are set as input and are in a high-impedance state
(without an external switching). Depending on the application, it may be
necessary to set the I/O lines in a defined state on power-up by using pull-
up or pull-down resistors. The design of the ME-5310 allows these to be
placed directly on the base board for all 64 lines as required. This is done
port by port with 4.7 kΩ resistors. Note that when pull-up resistors are
used, the current output of the lines is decreased (e.g. if R
up
= 4.7
kΩ I
max
= 3,1 mA).