I'm looking for a controller that is ethernet based has at least 16 x 12v relays (upgradeable?) and can be controlled via TCP/IP. I need multiple analogue inputs and also timers and the ability to store the input data for access by a pc later - does anyone know if such a device exists?

 

You can use a Beckhoff CX8090 | Embedded PC for Ethernet and EL2624 | 4-channel relay output terminal 125 V AC/30 V DC as needed.

 

Look at Honeywell's paperless recorders:

http://hpsweb.honeywell.com/Cultures/en-US/Products/Instrumentation/paperless/default.htm

(forum tends to insert spaces making long URLs unusable) or
http://tinyurl.com/632qtw

From your list of requirements, the following are met:
- multiple analog inputs

- 16 relay outputs

- ability to store input data for access by a PC

- ethernet access - HTTP server, FTP historical data, OPC server, Modbus master/slave functions

- weak point - timers; timers are available in math scripting functions

Given that your control functions are entirely undefined, it might or might not fit.

 

Here's a fairly economical solution from Automation Direct...

DL06 PLC
Model# D0-06DR-D
20 DC Inputs, 16 Relays Outputs
$239 US

Add Modbus/TCP EtherNet Plug-In Module
Model# H0-ECOM100
$199

Add 8-Channel Analog Input Plug-In Module
16 Bit, 0-20mA
Model# F0-08ADH-1
$129

Hope this helps!