Recent content by OldPfart

Cost was another - when transistors were expensive NPN was much cheaper than PNP - long time ago though.

Omron CJ1 PLCs with a serial card and external modem can do the job but not at that price. I do online programming via GSM/3G modems all the time and use the PLCs to send text messages to recipients via the same modem. The PLC has some nice functions such as calculate number of bytes for message...

I use PNP inputs (positive going high to turn on). I se NPN outputs (positive going low to turn on). I also use switch mode power supplies 240VAC/24VDC or 24VDC/24VDC for isolation. I do NOT ground the negative output from the switchmode or I would lose my isolation. Works fine. Never had a problem.

Omron CJ1, CS1, NSJ, CPiH, CP1L all share a function set including 64 bit floating point. Nothing wrong with BCD by the way. In the above PLCs you can select all timers and counters to be BCD or decimal for example. Most electricians understand BCD rather than decimal or hex. I am glad octal...

Omron have 64 bit floating point to the IEEE 754 standard and have had for some years now. How about BCD?

Here is a link to a site on busses. There are a loit of links to other sites also. http://ourworld.cs.com/rahulsebos/ I have recently started using a new I/O bus - CompoNet. Only available from Omron as far as I know at this stage and is administered by ODVA. Faster, deterministic (token ring)...

Here is a link to Omron cables http://forums.mrplc.com/index.php?download=349 and http://forums.mrplc.com/index.php?download=74

I am using a Mitsumi USB Bluetooth dongle and Promi Bluetooth serial port for online programming Omron CS/CJ PLCs all the time. Works great up to 100 metres - depending on what it has to punch through.

Here is another simpler link http://www.mikroelektronika.co.yu/english/product/books/PLCbook/plcbook.htm Hope it helps.

The Twido is a re-badged Idec (Izumi) with a different set of firmware. The software is terrible and I have thrown it away. It is even worse than Schneider's normal software. By the way, try pricing the up market stuff, it is a dear as ABs up market stuff. For relays with diodes and LEDs I...

If you buy an Omron ZEN or Schneider Zelio with screen and push buttons, you do not need software at all. The pushbuttons can program the unit very easily. If you want software for one of these simple devices then fine but I have the software for both of these and would not bother - it is...

Ah dear!!! The old CQM1. Have not used one for years. Definately download a manual for the PLC. It is absolutely essential to understand the memory map. Omron do not use I, Q, X or Y for external I/O. It is just a huge memory map of numbers but you have to know where evrything is in the memory...

I do not know whether it was you Marke or someone else that I referred to my download at MrPLC.com. The ladder version is slave only but should be able to be adapted to master. The simplest way is to use the CJ1M with an SCU comms unit. Use CX-Protocol to download the Modbus protocol available...

Oh dear!!! There go any thoughts I had about using AD. I quite often have 8-10 PLCs networked and lots of data flying around. Easier to work without having to use RX and TX quite frankly. Let the network look after itself.

The I/O table message is a real pain. I understand CX-One V1.1 is just about due. Hope they have fixed it. Seems to be something with updates to Windows XP. Never had it before. I normally shut it down (when it happens) with ctrl/alt/del. Open CX-Programmer again and all is well. Do not...